The term "" refers to a group of elements called lanthanides and actinides that are not often found in large, commercially valuable quantities. A) special earthsB) restricted mineralsC) rare earthsD) earth obscuresE) nonelastic minerals

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

the objects have the same charge is correct.

nathan lee

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.